Quizbowl science/Biology/Epinephrine

Epinephrine or adrenaline is an amino acid derivative hormone (polar). It is released from the adrenal medulla.

Functions

 * Acts on liver cells to increase blood glucose by:
 * 1) increasing glycogen breakdown and
 * 2) increasing gluconeogenesis.
 * Acts on muscle cells to make ATP by
 * 1) increasing glycogen breakdown
 * 2) increasing glycolysis
 * 3) increasing beta-oxidation (breaking down fatty acids to get energy)

Basically, the liver makes glucose, and the muscle breaks down that glucose, so ATP is available for fight-flight.

Mechanism
Epinephrine binds a G-protein coupled receptor, activating adenylate cyclase, which produces cAMP from ATP. This causes protein kinase A to become more active. PKA phosphorylates:
 * 1) makes glycogen synthase less active
 * 2) activates phosphorylase kinase -- makes glycogen phosphorylase more active (involved in glycogen breakdown -- glycogenolysis)